Grabbed one of two usb dongles last night to do some testing, and discovered, it has died.
No data output, no green LED. Red LED behaves as expected. Tried it on a different computer just to eliminate any driver/port issues, everything points to the dongle.
Being that I have a second one, I was able to swap 485, pic, and opto...nada...still dead. Those 3 socketed chips confirmed healthy.
I have 5V out of the dc-dc converter. Voltages on the FET are the same on the two dongles.
The one thing I can't easily check is the usb interface, other than to compare pin by pin with the two dongles. Have not done that yet.
I use the two dongles just for controller testing and config, the display is all E1.31, so the issue, for now, is low priority. That said, having something sitting on the bench that doesn't work, and at least not knowing whats causing it, drives me nuts..
Any thoughts?